This invention relates to a semiconductor device and a method of manufacturing a semiconductor device in which a structure is formed on a major surface of a semiconductor body and includes an insulating layer at said major surface, and in which a plasma and heating treatment is performed to passivate polysilicon grain boundaries and interface traps. Such methods are particularly important for the manufacture of devices such as charge-transfer devices and insulated gate field-effect transistor circuits in which electrodes are formed on the insulating layer and serve to control the passage of charge carriers in the underlying portion of the body by capacitance coupling across the insulating layer.
Liquid crystal display devices are now widely used. The performance of such display devices is influenced by the characteristics of thin film transistor ("TFT") components making up the display. It is known that the characteristics of the TFT may be greatly improved by the hydrogenation of polycrystalline silicon which is used to make the TFT. Plasma hydrogenation is the critical fabrication step in fabricating high performance polysilicon MOSFETs or TFTs. Such devices as shown in FIG. 1 are treated by plasma hydrogenation to improve device characteristics as illustrated in FIG. 2. However, normal plasma hydrogenation is a slow process which adds to the expense of and generates greater inefficiency in the manufacturing process. For example, typically the hydrogenation time is inversely proportional to the hydrogenation temperature, i.e. the higher the temperature at which hydrogenation is conducted, the shorter the hydrogenation time. However, this time temperature relationship can only be utilized to a limited extent because at a certain elevated temperature the device starts to lose hydrogen through out-diffusion and the performance characteristics of the device are degraded. As a result, the process has been limited to temperatures below the out-diffusion temperature and this leads to long hydrogenation times.